In an image forming apparatus, a photoconductive drum is energized by a roller charging system so that a latent image can be formed thereon. The roller charging system includes a module for overlapping DC output and AC output in an output module. It is difficult to maintain charging equalization without changing the DC output over time. The overlapping of the AC output is excellent for equalizing the charge and also for suppressing an increase in resistance at the time of roller energization. However, through discharge of excessive current, the photoconductive drum is susceptible to damage, such as abrasion of a film on the surface of the photoconductive drum. Thus, a configuration is proposed in which an absolute value of the charging potential is reduced and current discharge is reduced at a time no image is being formed while the overlapping AC output is provided.
However, the deterioration of the photoconductive drum continues due to the discharging of the photoconductive drum, even if the discharging is weak. Further, in a case in which the discharging is not executed at a time no image is being formed, the photoconductive drum is rotated in a state in which the potential of the photoconductive drum is low. Thus, a repulsive force between remaining transfer toner on the photoconductive drum and the photoconductive drum is weak, and the remaining transfer toner is easy to remove through a cleaning blade. As a result, there is a problem that the charging roller may be contaminated. To prevent contamination, the surface may be cleaned by using a cleaning member (bristle brush or the like) against the charging roller. However, the arrangement of the cleaning member is a significant factor of cost increase.